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authorChris Zankel <chris@zankel.net>2012-10-15 21:41:19 -0700
committerChris Zankel <chris@zankel.net>2012-10-15 21:41:19 -0700
commiteae8a416afe140df4b054c448476654db0d46bde (patch)
treebd5f48ace717e58d535bb3776c13b70360605f46 /arch/xtensa/lib
parentc88d8df0cc69fe0238f2c805a87cc67fb27a43fe (diff)
downloadlinux-eae8a416afe140df4b054c448476654db0d46bde.tar.gz
xtensa: fix memmove(), bcopy(), and memcpy().
- fix memmove to correctly handle overlapping src and dst; - fix memcpy loop ending conditions from signed '<=' to '!='; - modify bcopy to call memmove; Signed-off-by: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: Chris Zankel <chris@zankel.net>
Diffstat (limited to 'arch/xtensa/lib')
-rw-r--r--arch/xtensa/lib/memcopy.S309
1 files changed, 284 insertions, 25 deletions
diff --git a/arch/xtensa/lib/memcopy.S b/arch/xtensa/lib/memcopy.S
index ea59dcd0386..c48b80acb5f 100644
--- a/arch/xtensa/lib/memcopy.S
+++ b/arch/xtensa/lib/memcopy.S
@@ -6,7 +6,7 @@
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
- * Copyright (C) 2002 - 2005 Tensilica Inc.
+ * Copyright (C) 2002 - 2012 Tensilica Inc.
*/
#include <variant/core.h>
@@ -27,14 +27,11 @@
#endif
.endm
-
/*
* void *memcpy(void *dst, const void *src, size_t len);
- * void *memmove(void *dst, const void *src, size_t len);
- * void *bcopy(const void *src, void *dst, size_t len);
*
* This function is intended to do the same thing as the standard
- * library function memcpy() (or bcopy()) for most cases.
+ * library function memcpy() for most cases.
* However, where the source and/or destination references
* an instruction RAM or ROM or a data RAM or ROM, that
* source and/or destination will always be accessed with
@@ -45,9 +42,6 @@
* !!!!!!! Handling of IRAM/IROM has not yet
* !!!!!!! been implemented.
*
- * The bcopy version is provided here to avoid the overhead
- * of an extra call, for callers that require this convention.
- *
* The (general case) algorithm is as follows:
* If destination is unaligned, align it by conditionally
* copying 1 and 2 bytes.
@@ -76,17 +70,6 @@
*/
.text
- .align 4
- .global bcopy
- .type bcopy,@function
-bcopy:
- entry sp, 16 # minimal stack frame
- # a2=src, a3=dst, a4=len
- mov a5, a3 # copy dst so that a2 is return value
- mov a3, a2
- mov a2, a5
- j .Lcommon # go to common code for memcpy+bcopy
-
/*
* Byte by byte copy
@@ -107,7 +90,7 @@ bcopy:
s8i a6, a5, 0
addi a5, a5, 1
#if !XCHAL_HAVE_LOOPS
- blt a3, a7, .Lnextbyte
+ bne a3, a7, .Lnextbyte # continue loop if $a3:src != $a7:src_end
#endif /* !XCHAL_HAVE_LOOPS */
.Lbytecopydone:
retw
@@ -144,9 +127,6 @@ bcopy:
.global memcpy
.type memcpy,@function
memcpy:
- .global memmove
- .type memmove,@function
-memmove:
entry sp, 16 # minimal stack frame
# a2/ dst, a3/ src, a4/ len
@@ -182,7 +162,7 @@ memmove:
s32i a7, a5, 12
addi a5, a5, 16
#if !XCHAL_HAVE_LOOPS
- blt a3, a8, .Loop1
+ bne a3, a8, .Loop1 # continue loop if a3:src != a8:src_end
#endif /* !XCHAL_HAVE_LOOPS */
.Loop1done:
bbci.l a4, 3, .L2
@@ -260,7 +240,7 @@ memmove:
s32i a9, a5, 12
addi a5, a5, 16
#if !XCHAL_HAVE_LOOPS
- blt a3, a10, .Loop2
+ bne a3, a10, .Loop2 # continue loop if a3:src != a10:src_end
#endif /* !XCHAL_HAVE_LOOPS */
.Loop2done:
bbci.l a4, 3, .L12
@@ -305,6 +285,285 @@ memmove:
l8ui a6, a3, 0
s8i a6, a5, 0
retw
+
+
+/*
+ * void bcopy(const void *src, void *dest, size_t n);
+ */
+ .align 4
+ .global bcopy
+ .type bcopy,@function
+bcopy:
+ entry sp, 16 # minimal stack frame
+ # a2=src, a3=dst, a4=len
+ mov a5, a3
+ mov a3, a2
+ mov a2, a5
+ j .Lmovecommon # go to common code for memmove+bcopy
+
+/*
+ * void *memmove(void *dst, const void *src, size_t len);
+ *
+ * This function is intended to do the same thing as the standard
+ * library function memmove() for most cases.
+ * However, where the source and/or destination references
+ * an instruction RAM or ROM or a data RAM or ROM, that
+ * source and/or destination will always be accessed with
+ * 32-bit load and store instructions (as required for these
+ * types of devices).
+ *
+ * !!!!!!! XTFIXME:
+ * !!!!!!! Handling of IRAM/IROM has not yet
+ * !!!!!!! been implemented.
+ *
+ * The (general case) algorithm is as follows:
+ * If end of source doesn't overlap destination then use memcpy.
+ * Otherwise do memcpy backwards.
+ *
+ * Register use:
+ * a0/ return address
+ * a1/ stack pointer
+ * a2/ return value
+ * a3/ src
+ * a4/ length
+ * a5/ dst
+ * a6/ tmp
+ * a7/ tmp
+ * a8/ tmp
+ * a9/ tmp
+ * a10/ tmp
+ * a11/ tmp
+ */
+
+/*
+ * Byte by byte copy
+ */
+ .align 4
+ .byte 0 # 1 mod 4 alignment for LOOPNEZ
+ # (0 mod 4 alignment for LBEG)
+.Lbackbytecopy:
+#if XCHAL_HAVE_LOOPS
+ loopnez a4, .Lbackbytecopydone
+#else /* !XCHAL_HAVE_LOOPS */
+ beqz a4, .Lbackbytecopydone
+ sub a7, a3, a4 # a7 = start address for source
+#endif /* !XCHAL_HAVE_LOOPS */
+.Lbacknextbyte:
+ addi a3, a3, -1
+ l8ui a6, a3, 0
+ addi a5, a5, -1
+ s8i a6, a5, 0
+#if !XCHAL_HAVE_LOOPS
+ bne a3, a7, .Lbacknextbyte # continue loop if
+ # $a3:src != $a7:src_start
+#endif /* !XCHAL_HAVE_LOOPS */
+.Lbackbytecopydone:
+ retw
+
+/*
+ * Destination is unaligned
+ */
+
+ .align 4
+.Lbackdst1mod2: # dst is only byte aligned
+ _bltui a4, 7, .Lbackbytecopy # do short copies byte by byte
+
+ # copy 1 byte
+ addi a3, a3, -1
+ l8ui a6, a3, 0
+ addi a5, a5, -1
+ s8i a6, a5, 0
+ addi a4, a4, -1
+ _bbci.l a5, 1, .Lbackdstaligned # if dst is now aligned, then
+ # return to main algorithm
+.Lbackdst2mod4: # dst 16-bit aligned
+ # copy 2 bytes
+ _bltui a4, 6, .Lbackbytecopy # do short copies byte by byte
+ addi a3, a3, -2
+ l8ui a6, a3, 0
+ l8ui a7, a3, 1
+ addi a5, a5, -2
+ s8i a6, a5, 0
+ s8i a7, a5, 1
+ addi a4, a4, -2
+ j .Lbackdstaligned # dst is now aligned,
+ # return to main algorithm
+
+ .align 4
+ .global memmove
+ .type memmove,@function
+memmove:
+
+ entry sp, 16 # minimal stack frame
+ # a2/ dst, a3/ src, a4/ len
+ mov a5, a2 # copy dst so that a2 is return value
+.Lmovecommon:
+ sub a6, a5, a3
+ bgeu a6, a4, .Lcommon
+
+ add a5, a5, a4
+ add a3, a3, a4
+
+ _bbsi.l a5, 0, .Lbackdst1mod2 # if dst is 1 mod 2
+ _bbsi.l a5, 1, .Lbackdst2mod4 # if dst is 2 mod 4
+.Lbackdstaligned: # return here from .Lbackdst?mod? once dst is aligned
+ srli a7, a4, 4 # number of loop iterations with 16B
+ # per iteration
+ movi a8, 3 # if source is not aligned,
+ _bany a3, a8, .Lbacksrcunaligned # then use shifting copy
+ /*
+ * Destination and source are word-aligned, use word copy.
+ */
+ # copy 16 bytes per iteration for word-aligned dst and word-aligned src
+#if XCHAL_HAVE_LOOPS
+ loopnez a7, .backLoop1done
+#else /* !XCHAL_HAVE_LOOPS */
+ beqz a7, .backLoop1done
+ slli a8, a7, 4
+ sub a8, a3, a8 # a8 = start of first 16B source chunk
+#endif /* !XCHAL_HAVE_LOOPS */
+.backLoop1:
+ addi a3, a3, -16
+ l32i a7, a3, 12
+ l32i a6, a3, 8
+ addi a5, a5, -16
+ s32i a7, a5, 12
+ l32i a7, a3, 4
+ s32i a6, a5, 8
+ l32i a6, a3, 0
+ s32i a7, a5, 4
+ s32i a6, a5, 0
+#if !XCHAL_HAVE_LOOPS
+ bne a3, a8, .backLoop1 # continue loop if a3:src != a8:src_start
+#endif /* !XCHAL_HAVE_LOOPS */
+.backLoop1done:
+ bbci.l a4, 3, .Lback2
+ # copy 8 bytes
+ addi a3, a3, -8
+ l32i a6, a3, 0
+ l32i a7, a3, 4
+ addi a5, a5, -8
+ s32i a6, a5, 0
+ s32i a7, a5, 4
+.Lback2:
+ bbsi.l a4, 2, .Lback3
+ bbsi.l a4, 1, .Lback4
+ bbsi.l a4, 0, .Lback5
+ retw
+.Lback3:
+ # copy 4 bytes
+ addi a3, a3, -4
+ l32i a6, a3, 0
+ addi a5, a5, -4
+ s32i a6, a5, 0
+ bbsi.l a4, 1, .Lback4
+ bbsi.l a4, 0, .Lback5
+ retw
+.Lback4:
+ # copy 2 bytes
+ addi a3, a3, -2
+ l16ui a6, a3, 0
+ addi a5, a5, -2
+ s16i a6, a5, 0
+ bbsi.l a4, 0, .Lback5
+ retw
+.Lback5:
+ # copy 1 byte
+ addi a3, a3, -1
+ l8ui a6, a3, 0
+ addi a5, a5, -1
+ s8i a6, a5, 0
+ retw
+
+/*
+ * Destination is aligned, Source is unaligned
+ */
+
+ .align 4
+.Lbacksrcunaligned:
+ _beqz a4, .Lbackdone # avoid loading anything for zero-length copies
+ # copy 16 bytes per iteration for word-aligned dst and unaligned src
+ ssa8 a3 # set shift amount from byte offset
+#define SIM_CHECKS_ALIGNMENT 1 /* set to 1 when running on ISS with
+ * the lint or ferret client, or 0
+ * to save a few cycles */
+#if XCHAL_UNALIGNED_LOAD_EXCEPTION || SIM_CHECKS_ALIGNMENT
+ and a11, a3, a8 # save unalignment offset for below
+ sub a3, a3, a11 # align a3
+#endif
+ l32i a6, a3, 0 # load first word
+#if XCHAL_HAVE_LOOPS
+ loopnez a7, .backLoop2done
+#else /* !XCHAL_HAVE_LOOPS */
+ beqz a7, .backLoop2done
+ slli a10, a7, 4
+ sub a10, a3, a10 # a10 = start of first 16B source chunk
+#endif /* !XCHAL_HAVE_LOOPS */
+.backLoop2:
+ addi a3, a3, -16
+ l32i a7, a3, 12
+ l32i a8, a3, 8
+ addi a5, a5, -16
+ src_b a6, a7, a6
+ s32i a6, a5, 12
+ l32i a9, a3, 4
+ src_b a7, a8, a7
+ s32i a7, a5, 8
+ l32i a6, a3, 0
+ src_b a8, a9, a8
+ s32i a8, a5, 4
+ src_b a9, a6, a9
+ s32i a9, a5, 0
+#if !XCHAL_HAVE_LOOPS
+ bne a3, a10, .backLoop2 # continue loop if a3:src != a10:src_start
+#endif /* !XCHAL_HAVE_LOOPS */
+.backLoop2done:
+ bbci.l a4, 3, .Lback12
+ # copy 8 bytes
+ addi a3, a3, -8
+ l32i a7, a3, 4
+ l32i a8, a3, 0
+ addi a5, a5, -8
+ src_b a6, a7, a6
+ s32i a6, a5, 4
+ src_b a7, a8, a7
+ s32i a7, a5, 0
+ mov a6, a8
+.Lback12:
+ bbci.l a4, 2, .Lback13
+ # copy 4 bytes
+ addi a3, a3, -4
+ l32i a7, a3, 0
+ addi a5, a5, -4
+ src_b a6, a7, a6
+ s32i a6, a5, 0
+ mov a6, a7
+.Lback13:
+#if XCHAL_UNALIGNED_LOAD_EXCEPTION || SIM_CHECKS_ALIGNMENT
+ add a3, a3, a11 # readjust a3 with correct misalignment
+#endif
+ bbsi.l a4, 1, .Lback14
+ bbsi.l a4, 0, .Lback15
+.Lbackdone:
+ retw
+.Lback14:
+ # copy 2 bytes
+ addi a3, a3, -2
+ l8ui a6, a3, 0
+ l8ui a7, a3, 1
+ addi a5, a5, -2
+ s8i a6, a5, 0
+ s8i a7, a5, 1
+ bbsi.l a4, 0, .Lback15
+ retw
+.Lback15:
+ # copy 1 byte
+ addi a3, a3, -1
+ addi a5, a5, -1
+ l8ui a6, a3, 0
+ s8i a6, a5, 0
+ retw
+
/*
* Local Variables: